British Prime Minister David Cameron (R) speaks with European Council President...British Prime Minister David Cameron (R) speaks with European Council President Donald Tusk at Downing Street on January 31, 2016 in London, Britain.LessMore

British Prime Minister David Cameron (R) speaks with European Council President...British Prime Minister David Cameron (R) speaks with European Council President Donald Tusk at Downing Street on January 31, 2016 in London, Britain.LessMore

British Prime Minister David Cameron (R) speaks with European Council President...British Prime Minister David Cameron (R) speaks with European Council President Donald Tusk at Downing Street on January 31, 2016 in London, Britain.LessMore

British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the...More

British Prime Minister David Cameron (R) greets European Council President Donald...British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the benefits European Union migrants can claim in negotiations with EU president Donald Tusk ahead of a referendum on whether Britain should leave the bloc. Under Cameron's proposal, an 'emergency brake' to in-work benefits would come into force immediately after the referendum, due to be held by 2017. / AFP / Leon NealLessMore

British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the...More

British Prime Minister David Cameron (R) greets European Council President Donald...British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the benefits European Union migrants can claim in negotiations with EU president Donald Tusk ahead of a referendum on whether Britain should leave the bloc. Under Cameron's proposal, an 'emergency brake' to in-work benefits would come into force immediately after the referendum, due to be held by 2017. / AFP / Leon NealLessMore

British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the...More

British Prime Minister David Cameron (R) greets European Council President Donald...British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the benefits European Union migrants can claim in negotiations with EU president Donald Tusk ahead of a referendum on whether Britain should leave the bloc. Under Cameron's proposal, an 'emergency brake' to in-work benefits would come into force immediately after the referendum, due to be held by 2017. / AFP / Leon NealLessMore

British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the...More

British Prime Minister David Cameron (R) greets European Council President Donald...British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the benefits European Union migrants can claim in negotiations with EU president Donald Tusk ahead of a referendum on whether Britain should leave the bloc. Under Cameron's proposal, an 'emergency brake' to in-work benefits would come into force immediately after the referendum, due to be held by 2017. / AFP / Leon NealLessMore

British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the...More

British Prime Minister David Cameron (R) greets European Council President Donald...British Prime Minister David Cameron (R) greets European Council President Donald Tusk outside No 10 Downing Street in central London on January 31, 2016, ahead of their meeting.
Prime Minister David Cameron is to propose curbing the benefits European Union migrants can claim in negotiations with EU president Donald Tusk ahead of a referendum on whether Britain should leave the bloc. Under Cameron's proposal, an 'emergency brake' to in-work benefits would come into force immediately after the referendum, due to be held by 2017. / AFP / Leon NealLessMore

British Prime Minister David Cameron (R) speaks with European Council President...British Prime Minister David Cameron (R) speaks with European Council President Donald Tusk at Downing Street on January 31, 2016 in London, Britain.LessMore

British Prime Minister David Cameron (R) speaks with European Council President...British Prime Minister David Cameron (R) speaks with European Council President Donald Tusk at Downing Street on January 31, 2016 in London, Britain.LessMore